Ordinary walk-behind (soil) cultivating machines are also called “front-tine cultivating machines”, and such front-tine cultivating machines are constructed to transmit driving power from a drive source, such as an engine, to a cultivating shaft so that the machine can travel on a field through rotation of cultivating claws provided on the cultivating shaft while cultivating the field with the rotating cultivating claws. Advanced front-tine cultivating machines have been developed which employ an electric motor as the drive source in place of the engine, so as to lessen burdens on a human operator by enhancing operability of the machine and achieve an enhanced working environment (see, for example, Japanese Patent No. 3182930 and Japanese Patent Laid-Open Publication Nos. HEI-6-98601 and HEI-10-136702).
In the cultivating machine disclosed in Japanese Patent No. 3182930, a battery, electric motor and cultivating shaft are provided on a machine body frame. Electric power is supplied from the battery to the motor so that driving power of the motor is transmitted to the cultivating shaft and desired cultivating work or tillage is performed via cultivating claws provided on the cultivating shaft. The disclosed cultivating machine is shown in FIGS. 13A-13C.
In the electric cultivating machine 300 of FIGS. 13A-13C, the cultivating shaft 302 with the cultivating claws 303 provided thereon is supported by a lower portion of the machine body frame 301, a rotation shaft of the motor 304 (motor shaft) is disposed horizontally above the machine body frame 301, and the battery 305 is provided on a rear portion of the body frame 301. The electric cultivating machine 300 also includes an operating handle 306 extending rearward from the machine body frame 310, which has a main switch 311, lamp 312 and remaining battery power meter 313 on its upper central portion, a forward rotation switch 315 adjacent to a left grip 314 and a reverse rotation switch 317 adjacent to a right grip 317. These electric components 304, 305, 311-313, 315 and 317 are connected to a wire harness (group of conductors or leads) 318. The motor 304 is rotated in the forward direction in response to operation of the forward rotation switch 315 and rotated in the reverse direction in response to operation of the reverse rotation switch 317.
Generally, in cultivating a field via the cultivating claws, there would occur so-called “dashing” where the cultivating claws jump upward due to a reaction force given from the ground in response to the cultivating force (hereinafter “cultivation reaction force”). The dashing would degrade a linear traveling capability of the cultivating machine, which would result in insufficient cultivating performance and hence poor cultivating finish. The lighter in weight the cultivating machine 300, the more noticeable would become the tendencies.
Because the electric cultivating machine 300 of FIGS. 13A-13C includes the motor 304 and battery 305 located rearwardly of the cultivating shaft 302, not only sufficient consideration has to be given to the center of gravity of the cultivating machine 300, but also the human operator has to support the weights of the motor 304 and battery 305. As a consequence, burdens on the human operator would increase.
Further, the cultivating machine disclosed in Japanese Patent Laid-Open Publication No. HEI-6-98601 includes an electric motor and a cultivating shaft, both mounted on a machine body frame, so that driving power of the motor is transmitted to the cultivating shaft to perform desired cultivating work via cultivating claws provided on the cultivating shaft.
The cultivating machine disclosed in Japanese Patent Laid-Open Publication No. HEI-10-136702 is similar to the one disclosed in the HEI-6-98601 publication.
FIGS. 14A-14C show the cultivating machine 400 disclosed in the HEI-10-136702 publication, which includes a cultivating shaft 402 supported on a lower portion of a machine body frame 401, cultivating claws 403 provided on the cultivating shaft 402 and an electric motor (not shown) mounted on an upper portion of the machine body frame 401. The motor is covered with a cover 404. The electric cultivating machine 400 also includes an operating handle 405 extending rearward from the body frame, and a switch case 407 is mounted on a portion of the operating handle 405 adjacent to a right grip 406. Safety lock button 408 and switch lever 409 are mounted on the switch case 407. The switch lever 409 can be operated by the human operator holding the lever while depressing the safety lock button 408 with the thumb of his or her hand grasping the right grip 406. The motor can be rotated only when a micro switch 411 is kept ON via the switch lever 409. Reference numeral 412 represents a wire harness (group of conductors or leads), and 413 a left grip.
The cultivating machine 400 shown in FIGS. 14A-14C is not equipped with any battery; neither is the cultivating machine disclosed in the HEI-6-98601 publication. Therefore, the HEI-6-98601 and HEI-10-136702 publications fail to show an installed position of a battery in the cultivating machine.